Abstract: The present invention relates to security, or decorative elements, comprising a transparent, or translucent substrate, which may contain indicia or other visible features in or on its surface, and on at least part of the substrate surface, a first layer, comprising transition metal particles having an average diameter of from 5 nm to 500 nm and a binder, on at least part of the first layer a second layer, comprising an organic material and having a refractive index of from 1.2 to 2.3 and having a thickness of from 20 to 1000 nm, wherein the transition metal is silver, copper, gold and palladium, wherein the weight ratio of transition metal particles to binder in the first layer is in the range from 20:1 to 1:2 in case the binder is a polymeric binder, or wherein the weight ratio of transition metal particles to binder in the first layer is in the range from 5:1 to 1:15 in case the binder is an UV curable binder.

Abstract: The present invention provides a process for manufacturing a security feature for securing a value document, wherein said security feature exhibits a blue color upon viewing in transmitted light and a metallic yellow color upon viewing in Incident light. The manufacturing process comprises the following steps: a) printing a specific UV-Vis radiation curable ink on a transparent or partially transparent region of a substrate of a value document; b) heating the ink layer obtained at step a) at a temperature of about 55° C. to about 100° C. for at least one second so that the ink layer exhibits a metallic yellow color upon viewing in incident light; and c) UV-Vis curing the ink layer obtained at step b) to form the security feature.

Abstract: The present invention relates to a process for the preparation of thin silver nano-particles containing layers, which are produced directly on a substrate as part of a coating or printing process. The layers can show different colours in transmittance and reflectance. The invention further relates to decorative and security elements. When the layers are applied over a security element, such as a hologram, the obtained products may show different colours in reflection and transmission, an extremely bright optically variable image (OVD image). Depending on the thickness of the layer a more or less intensive metallic aspect appears.

Abstract: The present invention relates to metal oxide nanoparticles, a method for their production, a coating, or printing composition, comprising the metal oxide nanoparticles and the use of the composition for coating of surface relief micro- and nanostructures (e.g. holograms), manufacturing of optical waveguides, solar panels, light outcoupling layers for display and lighting devices and anti-reflection coatings. Holograms are bright and visible from any angle, when coated, or printed with the composition, comprising the metal oxide nanoparticles.

Abstract: The present invention relates to compositions, comprising silver nanoplatelets, wherein the number mean diameter of the silver nanoplatelets, present in the composition, is in the range of 50 to 150 nm with standard deviation being less than 60% and the number mean thickness of the silver nanoplatelets, present in the composition, is in the range of 5 to 30 nm with standard deviation being less than 50%, wherein the mean aspect ratio of the silver nanoplatelets is higher than 2.0 and the highest wavelength absorption maximum of the population of all silver nanoplatelets in the composition being within the range of 560 to 800 nm. A coating, comprising the composition, shows a blue color in transmission and a metallic yellow color in reflection.

Abstract: The present invention relates to security, or decorative elements, comprising a transparent, or translucent substrate, which may contain indicia or other visible features in or on its surface, and on at least part of the substrate surface, a first layer, comprising transition metal particles having an average diameter of from 5 nm to 500 nm and a binder, on at least part of the first layer a second layer, comprising an organic material and having a refractive index of from 1.2 to 2.3 and having a thickness of from 20 to 1000 nm, wherein the transition metal is silver, copper, gold and palladium, wherein the weight ratio of transition metal particles to binder in the first layer is in the range from 20:1 to 1:2 in case the binder is a polymeric binder, or wherein the weight ratio of transition metal particles to binder in the first layer is in the range from 5:1 to 1:15 in case the binder is an UV curable binder.

Abstract: The present invention relates to security elements, comprising (a) a substrate, (b) on at least part of the substrate surface a metal layer, (c) optionally on at least part of the metal layer a dielectric layer, (d) on at least part of the metal layer, or the dielectric layer, a layer obtained by overcoating the metal layer, or the dielectric layer with a composition, comprising (i) silver nanoparticles, (ii) a solvent, (iii) (surface) stabilizing agent(s) and (iv) optionally a binder, and (e) a protective layer on top of layer (d). The maximum absorption wavelength of the silver nanoparticles in layer (d) is controlled by the amount of (surface) stabilizing agent(s) and optionally binder relative to the amount of silver nanoparticles to be preferably in the range of 700 to 1600 nm.

Abstract: The present invention relates to surface functionalized titanium dioxide nanoparticles, a method for its production, a coating composition, comprising the surface functionalized titanium dioxide nanoparticles and the use of the coating composition for coating holo-grams, wave guides and solar panels. Holograms are bright and visible from any angle, when printed with the coating composition, comprising the surface functionalized tita-nium dioxide nanoparticles.

Abstract: The present invention relates to compositions, comprising silver nanoplatelets, wherein the mean diameter of the silver nanoplatelets, present in the composition, is in the range of 20 to 70 nm with standard deviation being less than 50% and the mean thickness of the silver nanoplatelets, present in the composition, is in the range of 5 to 30 nm with standard deviation being less than 50%, wherein the mean aspect ratio of the silver nanoplatelets is higher than 1.5, a process for its production, printing inks containing the compositions and their use in security products. The highest wavelength absorption maximum of the population of all silver nanoplatelets in the composition being within the range of 450 to 550 nm. A coating, comprising the composition, shows a red, or magenta color in transmission and a greenish-metallic color in reflection.

Abstract: A process for producing strongly adherent liquid crystal films on flexible substrates, security elements, obtainable by the process and security documents, including the security elements, may involve coating a flexible substrate first with a primer layer and then with a liquid crystal film the adherence of the liquid crystal film to the substrate is improved while keeping the optical performance of the liquid crystal film in an acceptable range.

Abstract: The present invention relates to a process for the preparation of thin silver nanoparticle layers, which are produced directly on a substrate as part of a coating or printing process. The layers show different colours in transmittance and reflectance. The layers do not show the typical conductivity of metallic layers, since the particles are essentially discrete particles which are not sintered. The invention further relates to decorative and security elements. When the layers are applied over a security element, such as a hologram, the obtained products show also different colours in reflection and transmission, an extremely bright optically variable image (OVD image) and high purity and contrast. Depending on the thickness of the layer a more or less intensive metallic aspect appears.

Abstract: Processes can produce strongly adherent, particularly embossed, films on flexible substrates. Security elements may be obtained by such processes as may be security documents, e.g., comprising the security elements. By coating a flexible substrate first with a primer layer and then with an embossed film, the adherence of the embossed film to the substrate may be improved while keeping the optical performance of the embossed film.

Abstract: The present invention relates to a process for the preparation of thin silver nano-particles containing layers, which are produced directly on a substrate as part of a coating or printing process. The layers can show different colours in transmittance and reflectance. The invention further relates to decorative and security elements. When the layers are applied over a security element, such as a hologram, the obtained products may show different colours in reflection and transmission, an extremely bright optically variable image (OVD image). Depending on the thickness of the layer a more or less intensive metallic aspect appears.

Abstract: The present invention relates to surface functionalized titanium dioxide nanoparticles, a method for its production, a coating composition, comprising the surface functionalized titanium dioxide nanoparticles and the use of the coating composition for coating holo-grams, wave guides and solar panels. Holograms are bright and visible from any angle, when printed with the coating composition, comprising the surface functionalized tita-nium dioxide nanoparticles.

Abstract: Disclosed herein is a method for forming a surface relief microstructure, including the steps of A) applying a curable composition to at least a portion of the frontside of the paper substrate, B) contacting at least a portion of the curable composition with surface relief microstructure, C) curing the composition by using at least one UV lamp which is arranged on the backside of the paper substrate, and D) depositing a metallic layer, and optionally a layer of a transparent high refractive index material, on at least a portion of the cured composition, wherein the UV lamp has an emission peak in a UV-A range of 320 nm to 400 nm and additionally in a near VIS range of 400 nm to 450 nm, the curable composition comprises a photoinitiator which absorbs in the UV-A range and also in the near VIS range.

Abstract: The instant invention pertains to a method for the production of brilliant glossy metal coatings on paper substrates. Further aspects of the invention are a paper product obtainable using the method and the use of such a paper for decorative or packaging purposes.

Abstract: Disclosed herein is a method for forming a surface relief microstructure, including the steps of A) applying a curable composition to at least a portion of the frontside of the paper substrate, B) contacting at least a portion of the curable composition with surface relief microstructure, C) curing the composition by using at least one UV lamp which is arranged on the backside of the paper substrate, and D) depositing a metallic layer, and optionally a layer of a transparent high refractive index material, on at least a portion of the cured composition, wherein the UV lamp has an emission peak in a UV-A range of 320 nm to 400 nm and additionally in a near VIS range of 400 nm to 450 nm, the curable composition comprises a photoinitiator which absorbs in the UV-A range and also in the near VIS range.

Abstract: A method and an apparatus for forming a surface relief microstructure, especially an optically variable image on a paper substrate are provided, the method comprising the steps of: A) applying a curable composition to at least a portion of the frontside of the paper substrate; B) contacting at least a portion of the curable composition with surface relief microstructure, especially optically variable image forming means; C) curing the composition by using at least one UV lamp (1, 2, 3) which is arranged on the backside of the paper substrate; D) optionally depositing a layer of a transparent high refractive index material and/or a metallic layer on at least a portion of the cured composition, wherein the lamp (1, 2, 3) having emission peak(s) in the UV-A and near VIS range and the curable composition comprises at least a photoinitiator which absorbs in the UV-A region and preferably in the near VIS range.

Abstract: The present invention relates to complex security elements based on liquid crystal coatings which are subsequently coated with specific metallic nano-shaped metal particles, a method for their manufacture, in particular on a glass, paper or on a plastic substrate and a security product obtainable using the security element. The security element may contain additionally an embossed surface relief microstructure, especially an optically variable image (an optically variable device, OVD), such as a hologram. A further aspect of the invention is the use of such a security element for the prevention of counterfeit or reproduction of a document of value.

Abstract: The present invention relates to the use of coating compositions, comprising shaped transition metal, especially silver, particles and a binder, wherein the ratio of pigment to binder is preferably such that the resulting coating shows an angle dependent color change, for the production of security elements and holograms. When the coating compositions of the present invention are used in coating a hologram the obtained products show a an angle dependent color change (flip/flop effect), different colors in reflection and transmission, an extremely bright OVD image and extremely strong rainbow effect, high purity and contrast.